Studied by 3 peopleVertebrates exhibit two major innovations:
Emergence of quadrupeds in the form of amphibians; evolution of the amniotic egg
Modifications of keratinous epidermal structures have given rise to
Scales, claws, hair, and feathers
The classes with the greatest percentage of threatened species are
Amphibians and mammals
Vertebrates are members of the kingdom _ and the phylum
Animalia; Chordata
Deuterstomes are divided into
Echinodermata and Chordata
Chordata share five key characteristics:
Notochord, dorsal hollow nerve cord, pharyngeal gill arches or slits, post-anal tail, and an endostyle/thyroid gland
Chordates are named for the
Notochord
The notochord is a
Flexible, rod-shaped mesodermal structure found in the embryonic stage of all chordates and the adult stage of some species
The notochord is strengthened with - similar to
Glycoproteins; cartilage and covered with a collagenous sheath
The notochord is located
Between the digestive tube and the nerve cord
The notochord provides
Rigid skeletal support as well as a flexible location for attachment of axial muscles
The notochord is replaced by the - in post embryonic vertebrates
Spine/vertebral column
Dorsal hollow nerve cord
Derived from ectoderm that rolls into a hollow tube during development, located dorsally to the notochord
Pharyngeal slits
Openings in the pharynx that extend to the outside environment
Endostyle
Strip of ciliated mucus-producing tissue in the floor of the pharynx; homologous to thyroid gland in vertebrates
Post-anal tail
Posterior elongation of the body that contains skeletal elements and muscles
The two clades of invertebrate Chordata are
Cephalochordata and Urochordata
Members of cephalochordata have - in the adult stage
A notochord, dorsal hollow tubular nerve cord, pharyngeal slits, endostyle/thyroid gland, and a post-anal tail
In cephalochordata, the notochord extends into the
Head
In cephalochordata, the nervous system is
Centered around a hollow nerve cord lying above the notochord
Lancelets are cephalochordates named for their
Blade like shape
Lancelets are - and usually found
A few centimeters long; buried in sand at the bottom of a warm, temperate tropical sea
Cephalochordates are - feeders
Suspension
In cephalochordata, the filtered water collects in
A gill chamber called the atrium
In cephalochordata, water exits through the
Atriopore
In cephalochordata, sexes are - and gametes are
Separate; released into water through the atriopore for external fertilization
Urochordata are also known as
Tunicates
Tunic
Cellulose-like carbohydrate material found in urochordates that covers the outer body
Adult urochordates do not have a
Notochord, dorsal hollow nerve cord, or a post-anal tail
Most tunicates are
Hermaphrodites
Tunicates are _ feeders
Suspension
Seawater enters the tunicate's body through its
Incurrent siphon
Seawater is expelled from tunicates through the
Excurrent siphon, which expels waste as well
Cranium
Bony, cartilaginous, or fibrous structure surrounding the brain, jaw, and facial bones
Craniata includes
Hagfishes, lampreys, and vertebrates
Vertebrates are the _ group of chordates
Largest
Agnatha
Jawless fishes: hagfishes and lampreys
Gnathostomes
Animals that possess a jaw; includes fish and tetrapods
Tetrapods include
Amphibians, reptiles, birds, and mammals
Tetrapods can be divided into two groups:
Amphibians and amniotes
Amniote'S are animals whose
Eggs contain four extraembryonic membranes that provide nutrition and a water-retaining environment for the embryos
Note
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